Application of Neck Circumference in Four-Variable Screening Tool for Early Prediction of Obstructive Sleep Apnea in Acute Ischemic Stroke Patients.

BACKGROUND: The purpose of this study was to validate and pilot the use of the four-variable screening tool (4V) and modified 4V tools to identify acute ischemic stroke and transient ischemic attack (TIA) patients at high risk of obstructive sleep apnea (OSA).

METHODS: Two modified scales, 4V-1 (ie, using neck circumference instead body mass index, regardless of gender) and 4V-2 (ie, as above but scored differently according to gender) were designed. These tools were used in a consecutive cohort of 124 acute ischemic stroke/TIA patients, together with the 4V-1, 4V-2, 4V, as well as the STOP-BANG, the Berlin questionnaire, and the Epworth Sleepiness Scale (ESS). Objective level 2 or level 3 polysomnography was used to confirm OSA and its severity. Both questionnaires and polysomnography were completed within 1 week from symptom onset.

RESULTS: Area under the curve (AUC) of 4V was 0.807 (P< .0001) while AUC of STOP-BANG, Berlin Questionnaire and ESS were .701 (P< .0001), .704 (P< .0001) and .576 (P = .1556), respectively. AUC of 4V was greater than of STOP-BANG (z = 2.200, P = .0220), Berlin (z = 2.024, P = .0430) and ESS (z = 3.363, P = .0003). AUC of modified 4V-1 and modified 4V-2 were .824 (P< .001) and .835 (P< .001), respectively. Performance of modified 4V-2 was higher versus modified 4V-1 (z = 2.111, P = .0348) and higher but not significantly so to regular 4V (z = 1.784, P = .0744).

CONCLUSIONS: Neck circumference scored by gender is a useful substitution to body mass index in the 4V when screening OSA at early stages of ischemic stroke/TIA patients.